Control system



Feb. 27, 1934. w. M. HUTCHISON 1,948,760

CONTROL SYSTEM Filed May 28, 1930 2 Sheets-Sheet 1 INVENTOR Pl/i/ifam M. Hare/4150a AT RNIEY 1 Feb. 27, 1934. w, M. HUTCHISON 1,948,760

CONTROL SYSTEM File ay 2 1950 2 Sheets-Sheet 2 INVENTOR William M. Hufc/usorz ATTORNEY Patented Feb. 27, 1934 UNITED STATES PATENT OFFICE CONTROL SYSTEM William Martin Hutchison,

Pittsburgh, Pa...

vania Application May 28, 1930. Serial No. 456,315

6 Claims.

My invention relates, generally, to relays and, more particularly, to overload current and line voltage relays.

In the operation of electrical apparatus, as 'for example railway motors, it is necessary to protect the apparatus from high current overloads and also against fluctuations in the voltage of the source of power.

Heretofore it has been customary to provide I separate current relays for overload protection and separate voltage relays for voltage protection, the relays having independent contact members which controlled the operation of line switches to disconnect the motors or other apparatus from the source of power.

When a plurality of motors are connected to the same supply source in series or parallel circuit relation, as is customary in railway applications, a large number of relays and contact members are required, in order to provide adequate protection, if independent relays are used.

An object of my invention, generally stated, is to provide a combination current and voltage relay which shall be simple and efficient in operation, and which may be readily and economically manufactured.

A more specific object of my invention is to provide for actuating a contact member by any one of a plurality of operating mechanisms.

Another object of the invention is to reduce the total number of contact members required in a circuit, by combining a plurality of current relay contact members and voltage relay contact members.

For a fuller understanding of the nature and objects of the invention, reference may be had to the following detailed description, taken in conjunction with the accompanying drawings, in which:

Figure l is a view, in front elevation, of a relay constructed in accordance with my invention;

Fig. 2 is a diagrammatic view illustrating how the relay may be connected into a control circuit;

Fig. 3 is a view, in side elevation, of the relay shown in Fig. 1.

Fig. 4 is a view, partly in elevation and partly in section, taken along the line IVIV of Fig. 1.

Referring now to the drawings, the combination relay shown comprises a frame 10 which is mounted on an insulating panel 11. In this embodiment of the invention, two current relays 12 are mounted on the frame 10. The relays 12 each comprise a core 13, a current coil 14 and an armature 15 pivotally mounted on the frame 10. The armatures 15 are each normally biased to the open position by a spring 16, the tension of which may be varied by adjusting a screw 17, in order to change the value of current required in the coil 14 to operate the relay.

It will be observed that a yoke 18 is pivotally mounted on the frame 10 and is disposed to be actuated by either of the armatures 15. The yoke 18 is normally biased to the position shown in the drawings by a spring 19. When either one of the armatures 15, of the relays 12, is actuated towards its core 13, the lower end of the armature strikes a set screw 20, one of which is provided at each end of the yoke 18, and thereby actuates the yoke 18 about its pivotal axis.

In order to perform switching operations, contact members 21 and 22 are mounted on, and insulated from the yoke 18 by means of strips 23, composed of insulating material. While in this instance only two contact members are carried by the yoke 18, it will be readily understood that more may be provided if it is so desired.

It will be observed that contact members 24 and 25 are provided to engage the contact members 21 and 22 respectively. The contact members 24 and 25 are mounted on an insulating block 26 carried by a pivotally mounted armature 27, which is disposed to be actuated by a voltage coil 28. When the coil 28 is energized by a predetermined voltage, the armature 27 is attracted towards a core 29, which is magnetized by the coil 28. The armature27 is normally biased to the position shown in the drawings by a spring 30.

When the yoke 18 is actuated by either one of the armatures 15, the lower end of the yoke is engaged by a latching lever 31. Referring to Fig. 3 it will be observed that the lever 31 is pivotally mounted on a bracket 32 and is biased upwardly by a spring 33. Consequently the yoke 18 will be retained in the tripped position by the lever 31 after the coil 14 is deenergized and the armature 15 has returned to its normal position.

In order that the yoke 18 may be returned to its normal position, a reset coil 34 is provided. When the coil 34 is energized, an armature 35 strikes the lower end of the lever 31, which unlatches the yoke 18 and permits the spring 19 to return the yoke 18 to its normal or untripped" position.

In the operation of the relay, the contact members 24 and 25 may be actuated into engagement with the contact members 21 and 22 respectively, when the yoke 18 is biased to its normal po- 17 an overload relay for each motor.

sition by the spring 19, by energizing the voltage coil 28 with a predetermined voltage. When the armature 27 is actuated towards the coil 28, the contact members 24 and 25, carried by the armature 27, are actuated into engagement with the contact members 21 and 22, respectively.

When either of the current coils 14 is energized by a predetermined current, its armature 15 actuates the yoke 18 to the tripped position, thereby interrupting the circuits through the contact members 21 and 24, and 22 and 25. As previously explained, when the yoke 18 is actuated to its tripped position, it is held in this position by the latching lever 31 until the reset coil 34 is energized which releases the latching mechanism and permits the yoke 18 to be returned to its normal position.

In order to more clearly explain the operation and functioning of the relay, a control system is illustrated in Fig. 2 showing how the relay may be connected into a circuit. It will be observed that two motors 36 and 37 are disposed to be connected to a trolley conductor 38 in parallel circuit relation, when line switches 39 and 40 are closed.

In railway service, it is customary to connect the motors in series circuit relation for starting the car and then change to a parallel connection after the car has been accelerated to a predetermined speed. In order that the motors will be protected against overloads while connected in series circuit relation, as well as when in parallel circuit relation, it is necessary to provide In order to simplify the drawings, only the parallel connections are shown.

In case of an overload or short circuit on one motor, it is necessary to disconnect both motors from the source of power in order to prevent the remaining motor from being overloaded after the first motor has been disconnected. It is also necessary to protect the motors against fluctuations in the voltage of the source of power.

Referring to Fig. 2, it will be observed that one of the current coils 14 is connected in series with each of the motors 36 and 37, thereby being responsive to the current flowing in the motors. The voltage coil 28 may be energized by actuating a control switch 41 to the on position, which completes the circuit from the trolley conductor 38, through the coil 28 to ground. If the voltage of the supply source is a predetermined value the contact members 24 and are actuated into engagement with the contact members 21 and 22, respectively, thereby simultaneously energizing the actuating coils of the line switches 39 and 40. Upon the energization of the coils of the line switches, the mo- I tors 36 and 37 are connected to the power source in parallel circuit relation.

In case the current in either motor exceeds a predetermined value, the corresponding current coil 14 actuates the yoke 18 to interrupt the 3 circuit through the contact members 21 and 24,

also 22 and 25, which deenergizes the coils of the line switches 39 and 40, thereby simultaneously disconnecting the motors 36 and 37 from the power SOlll'CG.

, switch 41 is actuated to the off position, thereby permitting the spring to actuate the armature 27 to separate the contact members 21 and 24, also 22 and 25.

In case the yoke 18 is actuated to the tripped position by either of the current coils 14, it will be engaged by the latching lever 31 and held in this position until the reset coil 34 is energized by closing the push button switch 42. Energizing the coil 34 causes the lever 31 to release the yoke 18 and permit it to be returned to its normal position by the spring 19.

While I have shown a relay having only two current coils, it will be readily seen that more current elements may be added if it is so desired. The yoke 18 may be so extended that it may be actuated by the armatures of the additional current elements in the same manner as illustrated in the present relay. Additional contact members may be easily added for controlling additional circuits if desired.

It will be evident that the combination relay herein described may be utilized to protect a plurality of motors, or other electrical apparatus, against overloads and also fluctuations in the voltage of the power source. Since a single set of contact members may be utilized for the current and voltage elements, the total number of contact points required in a circuit is decreased, consequently the chances of contact failure are reduced.

Since numerous changes may be made in the above-described construction and different embodiments of the invention may be made Without departing from the spirit and scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim as my invention:

1. In a relay, in combination, contact members disposed to be actuated into and out of engagement to perform switching operations, a voltage coil for actuating some of the contact members into engagement with the other contact members when energized, means for interrupting the engagement between the contact members when the voltage coil is deenergized, and a plurality of current coils each having an independent armature member for actuating said other contact members when energized by a predetermined current whereby the contact members are separated on the failure of voltage or the flow of a predetermined current.

2. In a relay, in combination, a. plurality of contact members arranged in pairs to perform switching operations, a plurality of current coils, an independent armature member for each coil, means disposed to be operated by the armature member of each coil singly to separate all the pairs of contact members upon the energization of the coil by a predetermined current, a voltage coil disposed to establish engagement between the pairs of contact members when energized and means associated with the voltage coil to interrupt the engagement between the pairs of contact members when the voltage applied to the coil decreases to a predetermined value.

3. In a relay, in combination, contact members disposed to be actuated into and out of engagement to perform switching operations, a plurality of current coils each having an independent armature member, means disposed to be operated by each armature independently of the other armatures to separate the contact members upon the energization of its respective coil by a predetermined current, a voltage coil disposed to establish engagement between the contact members when energized, and means associated with the voltage coil to interrupt the engagement between the contact members when the voltage applied to the coil decreases to a predetermined value.

4. In a relay, in combination, contact members disposed to be actuated into and out of engagement to perform switching operations, a current coil, means disposed to be operated by the current coil to actuate the contact members upon the energization of the coil by a predetermined current, means for retaining the contact members in the position to which they are actuated by the current coil, a voltage coil, and means associated with the voltage coil to actuate the contact members when a predetermined voltage is applied to the coil.

5. In a relay, in combination, contact members disposed to be actuated into and out of engagement to perform switching operations, a plurality of coils disposed to be energized by independent circuits, each coil having an independent armature member means disposed to be operated by any one of said armature members to actuate the contact members upon the energization of its respective coil by a predetermined current.

6. In a relay, in combination, contact members disposed to be actuated into and out of engagement to perform switching operations, a plurality of current coils each disposed to operate an independent armature member when energized, means disposed to be operated by each armature independently of the other armatures to actuate the contact members to a predetermined position, and means for retaining the contact members in said position after the current coil is deenergized.

WILLIAM M. HUTCHISON. 

